1. Technical Field
The technology described herein is generally related to the field of integrated circuits (“IC”); IC structures and devices are also referred to hereinafter as “chip(s),” and “dice” or “die.”
2. Description of Related Art
The integrated circuit field of technology is well established. Many publications describe the details of commonly known techniques used in the fabrication of integrated circuits that can be generally employed in the fabrication of complex, three-dimensional, IC structures and devices; see e.g., Silicon Processes, Vol. 1–3, copyright 1995, Lattice Press, Lattice Semiconductor Corporation, Hillsboro, Oreg. Moreover, the individual steps of such a process can be performed using commercially available IC fabrication machines. The use of such machines and commonly used fabrication step techniques will be referred to hereinafter as simply: “in a known manner.” As specifically helpful to an understanding of the present invention, approximate technical data are disclosed herein based upon current technology; future developments in this art may call for appropriate adjustments as would be apparent to one skilled in the art.
Certain commercial products employing IC chips require the state of a digital output signal stays at a predetermined logic signal, “HIGH” or “LOW,” even when supply voltages are below the threshold voltage of the output stage driver field effect transistors (“FETs”). For example, a voltage monitoring instrument needs to transmit accurately the true output of the circuitry being monitored. Other examples of such products are power-on reset generators, microprocessor supervisors, and chip-select drivers.
Known manner complementary metal-oxide-semiconductor (“CMOS”) circuit designs may not result in a “guaranteed” output state when the supply voltage falls below a threshold voltage of the output stage driver FETs. On the other hand, lowering the threshold voltage may improve performance of an IC, but generally requires a change to the wafer-level IC dice fabrication processes. However, lowering the threshold voltage may have undesired electrical effects such as increasing leakage currents. Therefore, there are competing interests for the IC designer to consider.
There is a need for improved electronic circuits for commercial products where output stage signals are a critical factor of performance.